Morphine is a known analgesic compound isolated from the opium poppy and has the following structural formula:

Although morphine is a potent analgesic, it possesses several undesirable side effects, including, but not limited to, physical dependence. Therefore, several compounds have been developed by addition or substitution to the basic morphine skeleton. Several such compounds are described in U.S. Pat. No. 5,219,347, issued Jun. 15, 1993 to Kanematsu, et al.; U.S. Pat. Nos. 5,912,347 and 6,242,604, issued Jun. 15, 1999 and Jun. 5, 2001 to Hudlicky et al.; U.S. Pat. No. 6,150,524, issued Nov. 21, 2000 to Hartmann et al.; U.S. Pat. No. 6,323,212, issued Nov. 27, 2001 to Nagese et al. and European Patent No. 577,847, published Jan. 12, 1994; European Patent No. 242,417, published Feb. 10, 1993; and European Patent No. 632,041, published Jan. 4, 1995. When a methoxy group is substituted for the 3-hydroxyl group, the compound is codeine, an opioid often used as an analgesic and also in cough medications for its antitussive effects.
Various substituents of the morphine structure are not required for a narcotic effect. Such morphine derivatives are classed as morphinans. As used in the present application, a morphinan is a compound similar to morphine but lacks the 4,5-ether, and may also lack the 7,8 alkenyl bond, and has the following structural formula:

The numbering system used with compound (II) is a “conventional numbering system used in describing morphinans and corresponds to the numbering of morphine (I) used above. It is recognized that the International Union of Pure and Applied Chemistry (IUPAC) numbering system is different, so that, e.g., the Merck Index (12 ed., 1996) names the compound Morphinan in monograph 6358 at pp. 1073-74 as [4aR(4aα,10α,10aα)]-1,1,4,9,10,10a-Hexahydro-2H-10,4a-iminoethano) phenanthrene and has the following structural formula:

In the present application, the “conventional” numbering system is used unless otherwise noted.
Some morphinans are agonists, producing an analgesic effect while other morphinans are antagonists, blocking the effect of morphine and morphine agonists. Still other morphinans exhibit a combined agonist/antagonist activity, producing an analgesic effect itself while blocking the agonist activity of other morphinans. Finally, some morphinans, including the compound morphinan (IIa), exhibit no biological activity. The so-called “morphine rule,” or Becket-Casey rule, requires (1) an aromatic ring (2) attached to a quaternary center which is connected to (3) a tertiary nitrogen which is (4) located two carbon atoms away. It has been found that substitution of the nitrogen methyl group by allyl, n-propyl, a substituted allyl, propynyl, cyclopropyl methyl, and cyclobutyl methyl results in morphine antagonists.
Representative morphinans are shown in the following patents: U.S. Pat. No. 3,275,638, issued Sep. 27, 1966 to Sawa et al.; U.S. Pat. No. 3,819,635, issued Jun. 25, 1974 to Pachter et al.; U.S. Pat. No. 4,228,285, issued Oct. 14, 1980; U.S. Pat. No. 4,673,679, issued Jun. 16, 1987 to Aungst et al.; U.S. Pat. No. 4,912,114, issued Mar. 27, 1990 to L. Revesz and U.K. Patent No. 2,175,898, published Dec. 10, 1986; U.S. Pat. No. 5,071,985, issued Dec. 10, 1991 to Andre et al.; U.S. Pat. No. 5,504,208, issued Apr. 2, 1996 to Sobotik et al.; U.S. Pat. No. 6,166,211, issued Dec. 26, 2000 to Cain et al.; and U.K. Patent No. 1,038,732, published Aug. 2, 1967.
A further simplification of the morphine structure involves elimination of one of the cycloalkane rings to produce 6.7 benzomorphans having the structural formula:

Representative benzomorphans are shown in the following patents: U.S. Pat. No. 3,764,606, issued Oct. 9, 1973 to Akkerman et al.; U.S. Pat. No. 3,936,463, issued Feb. 3, 1976 to Behner et al.; U.S. Pat. No. 4,029,798, issued Jun. 14, 1977 to Yamamoto et al.; U.S. Pat. No. 4,128,548, issued Dec. 5, 1978 to Akkerman et al.; U.S. Pat. No. 4,288,444, issued Sep. 8, 1981 to Akkerman et al.; U.S. Pat. No. 5,354,758, issued Oct. 11, 1994 to Lawson et al.; U.S. Pat. Nos. 5,607,941, issued Mar. 4, 1997 to Merz et al., 5,731,318, issued Mar. 24, 1998 to Carter et al., and Canadian Patent No. 2,072,814, published Jan. 3, 1993; U.K. Patent No. 1,077,711, published Aug. 2, 1967.
Another class of morphine derivatives, the morphones, feature an oxidized oxygen atom at C6, and have the following structural formula:

Representative morphone compounds are described in the following patents: U.S. Pat. No. 4,230,712, issued Oct. 28, 1980 to Kotick et al.; U.S. Pat. No. 4,272,541, issued Jun. 9, 1981, also to Kotick et al.; U.S. Pat. No. 4,388,463, issued Jun. 14, 1983 to Brossi et al.; U.S. Pat. No. 4,390,699, issued Jun. 28, 1983, also to Brossi et al.; U.S. Pat. No. 5,780,479, issued Jul. 14, 1998 to S. W. Kim; and U.S. Pat. No. 6,271,239, issued Aug. 7, 2001 to Portoghese et al.
Previous work in this area has generally focused upon the investigation of the use of these morphine derivatives as analgesics, morphine antagonists, or antitussives. However, recent literature has reported potential new uses for some morphine derivatives which may not be mediated through morphine receptors. A series of compounds that are modified in position 3 and 17 of the morphinan ring system have been reported to exhibit anticonvulsant effects in Bioorg. Med. Chem. Lett. 11, 1651-1654 (2001). A series of stereoisomeric 6,7-benzomorphan derivatives with modified N-substituents are described in J. Med. Chem. 40, 2922-2930 (1997) as antagonizing the N-methyl-D-aspartate (NMDA) receptor-channel complex in vitro and in vivo. (+)-Pentazocine, a sigma receptor agonist, has been demonstrated to have unique survival activity on cortical neurons through sigma receptors in Cell. Mol. Neurobiol. 20(6), 695-702 (2000). Two homologs in the (+)-(1S,5S,9S)-normetazocine series, N-pent-4-enyl and N-hex-5-enyl, are reported in J. Med. Chem. 43(26), 5030-5036 (2000), to have high-affinity and selective σ1-ligands (Ki=2 nM, σ2/σ1=1250, and 1 nM, σ2/σ1=750, resp.); in contrast, N-allylnormetazocine has relatively poor affinity at al, and its σ1/σ2 ratio is <100.
Recent advances in the research of neurodegenerative diseases of the central nervous system have revealed that the opioids may play a role in modulating the expression of inflammatory factors such as proinflammatory cytokines, free radicals and metabolites of arachidonic acid in microglia and in the mediation of immune-related neurodegeneration, Adv. Exp. Med. Biol. 402: 29-33 (1996); Mov. Disord. 12: 855-858 (1997). Naloxone, a morphine antagonist, is disclosed in J. Pharmacol. Exp. Therap. 293, 607-617 (2000) to protect rat dopaminergic neurons against inflammatory damage through inhibition of microglia activation and superoxide generation.
The potential for the development of tolerance and physical dependence with repeated opioid use is a characteristic feature of all the opioid drugs, and the possibility of developing psychological dependence (i.e., addiction) is one of the major concerns in the use of the treatment of pain with opioids. Another major concern associated with the use of opioids is the diversion of these drugs from the patient in pain to another (non-patient) for recreational purposes, e.g., to an addict. Thus, it is desirable to provide opioid and opioid-like compounds useful for the prevention or treatment of various disorders as described herein.
Aerobic organisms, which derive their energy from the reduction of oxygen, are susceptible to the damaging actions of the small amounts of O2—, OH and H2O2 that inevitably form during the metabolism of oxygen, especially in the reduction of oxygen by the electron transfer system of mitochondria. These three species, together with unstable intermediates in the peroxidation of lipids, are referred to as Reactive Oxygen Species (ROS). Many diseases such as, but not limited to, Alzheimer's Disease, Parkinson's disease, aging, cancer, myocardial infarction, atherosclerosis, autoimmune diseases, radiation injury, emphysema, sunburn, and joint disease (a. Everything cytokine & beyond, Cytokines Mini-Reviews, Chapter:Reactive Oxygen Species (ROS), Copyright 2003©R&D Systems; b. Channon K M, Guzik T J, Mechanisms of superoxide production in human blood vessels: relationship to endothelial dysfunction, clinical and genetic risk factors. J. Physiol. Pharmacol. 2002, 53(4), 515-524; c. Henrotin, Y E et al. The role of reactive oxygen species in homeostasis and degradation of cartilage. OsteoArthritis and Cartilage 2003, 11, 747-755; d. Arzimanoglou A et al. Epilepsy and neuroprotection: An illustrated review article. Epileptic Disord 2002, 3, 173-82; e. Seidman M D et al., Biologic activity of mitochondrial metabolites on aging and age-related hearing loss.
Am J Otol 2000, 21(2):161-7.) are linked to damage from ROS as a result of an imbalance between radical-generating and radical-scavenging systems—a condition called oxidative stress. The discovery by McCord and Fridovich (McCord, J. M. & I. Fridovich J. Biol. Chem. 1969, 244:6049) of the superoxide dismutase (SOD) activity of erythrocuprein, together with the finding that almost all mammalian cells contain SOD, suggests a physiological role of at least the central ROS, superoxide.
TNF-α (tissue necrosis factor), a cytokine that plays a critical role in eliciting the body's inflammatory response and is present in abnormally high levels in the joints of individuals suffering from rheumatoid arthritis, has been implicated as an immune modulator in the immune system. Inhibitors of TNF-□ have been shown to halt the progression of cartilage destruction and relieve the symptoms of severe arthritis. Approximately 30% of moderate to severe arthritic patients are not responsive to these treatments (Feldman M, Maini R N, Discovery of TNF-α as a therapeutic target in rheumatoid arthritis: preclinical and clinical studies. Joint Bone Spine 2002, 69, 12-18; Lipsky P E, et al. Infliximab and methotrexate in the treatment of rheumatoid arthritis. N. Engl. J. Med. 2000, 343 1954-1602). Animal studies in association with studies conducted in humans indicate a potential role for TNF modulation in Crohn's disease, ulcerative colitis, insulin resistance, multiple sclerosis, multiple organ failure, pulmonary fibrosis, and atherosclerosis (Newton R C, Decieco C P, Therapeutic potential and strategies for inhibiting tumor necrosis factor-a. J. Med. Chem. 1999, 42, 2295-2314).
During the course of sepsis, nitric oxide (NO) is produced. Its metabolites impair normal vascular reactivity, in conjunction with elevated endotoxin levels. Inhibitors of NO synthase restore blood pressure, lower the cardiac index and increase pulmonary and systemic vascular resistance. Selective NOS inhibitors targeted against iNOS may prove to be beneficial. A small study with an inhibitor of NOS action, namely methylene blue, which inhibits the associated guanylyl cyclase enzyme, has indicated beneficial effects versus the cardiovascular parameters described above in patients with septic shock [Preiser, J C, Lejeune P, Roman A, et al. Methylene blue administration in septic shock: a clinical trial. Crit. Care Med., 23: 259-64 (1995); Gachot B, Bedos J P, Veber B, et al. Short term effects of methylene blue on hemodynamics and gas exchange in humans with septic shock, Intensive Care Med 21:1027-31; Vincent, J L, Sun Q, Dubois, M-J, Clinical Trials of Immunomodulatory Therapies in Severe Sepsis and Septic Shock, CID, 34: 1084-1093 (2002)].